DOE OSTI2020
La3O2F5 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are six inequivalent La3+ sites. In the first La3+ site, La3+ is bonded in a 9-coordinate geometry to two equivalent O2- and seven F1- atoms. There are one shorter (2.55 Å) and one longer (2.73 Å) La–O bond lengths. There are a spread of La–F bond distances ranging from 2.36–2.63 Å. In the second La3+ site, La3+ is bonded in a distorted body-centered cubic geometry to four O2- and four F1- atoms. There are a spread of La–O bond distances ranging from 2.34–2.41 Å. There are a spread of La–F bond distances ranging from 2.71–2.84 Å. In the third La3+ site, La3+ is bonded in a 10-coordinate geometry to two equivalent O2- and eight F1- atoms. There are one shorter (2.28 Å) and one longer (3.01 Å) La–O bond lengths. There are a spread of La–F bond distances ranging from 2.40–2.97 Å. In the fourth La3+ site, La3+ is bonded in a 9-coordinate geometry to four O2- and five F1- atoms. There are a spread of La–O bond distances ranging from 2.39–2.55 Å. There are a spread of La–F bond distances ranging from 2.54–2.91 Å. In the fifth La3+ site, La3+ is bonded in a distorted body-centered cubic geometry to two equivalent O2- and six F1- atoms. Both La–O bond lengths are 2.38 Å. There are a spread of La–F bond distances ranging from 2.42–2.62 Å. In the sixth La3+ site, La3+ is bonded in a body-centered cubic geometry to two equivalent O2- and six F1- atoms. There are one shorter (2.33 Å) and one longer (2.45 Å) La–O bond lengths. There are a spread of La–F bond distances ranging from 2.46–2.56 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to four La3+ and six F1- atoms. There are a spread of O–F bond distances ranging from 2.55–3.09 Å. In the second O2- site, O2- is bonded in a 4-coordinate geometry to four La3+ atoms. In the third O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to four La3+ atoms. In the fourth O2- site, O2- is bonded to four La3+ atoms to form distorted OLa4 tetrahedra that share corners with four equivalent OLa4 tetrahedra, corners with six FLa4 tetrahedra, and an edgeedge with one FLa4 tetrahedra. There are ten inequivalent F1- sites. In the first F1- site, F1- is bonded in a 3-coordinate geometry to three La3+ atoms. In the second F1- site, F1- is bonded to four La3+ atoms to form distorted FLa4 tetrahedra that share corners with four equivalent OLa4 tetrahedra, corners with eight FLa4 tetrahedra, and edges with four equivalent FLa4 tetrahedra. In the third F1- site, F1- is bonded in a 3-coordinate geometry to four La3+ and one O2- atom. In the fourth F1- site, F1- is bonded to four La3+ and four equivalent O2- atoms to form a mixture of distorted corner and face-sharing FLa4O4 tetrahedra. In the fifth F1- site, F1- is bonded in a 3-coordinate geometry to four La3+ atoms. In the sixth F1- site, F1- is bonded to four La3+ atoms to form a mixture of distorted edge and corner-sharing FLa4 tetrahedra. In the seventh F1- site, F1- is bonded to four La3+ atoms to form distorted FLa4 tetrahedra that share corners with two equivalent OLa4 tetrahedra, corners with six FLa4 tetrahedra, an edgeedge with one OLa4 tetrahedra, and edges with five FLa4 tetrahedra. In the eighth F1- site, F1- is bonded in a 4-coordinate geometry to four La3+ atoms. In the ninth F1- site, F1- is bonded in a 2-coordinate geometry to two equivalent La3+ atoms. In the tenth F1- site, F1- is bonded in a 2-coordinate geometry to three La3+ and one O2- atom.